Stringing block apparatus



Feb. 12, 1963 R. CRONKRQIGHT 3,077,337

STRINGING BLOCK APPARATUS Filed April 20, 1961 INVENTOR. Pass/s21;CEONKRIG'HT A TTOE/VE KS United States Patent 3,077,337 Patented Feb.12, 1963 nice 3,077,337 STRINGING BLGCK APPARATUS Russell Cronkright,2%)60 Kline St, Denver, Colo. Filed Apr. 20, 1%1, Ser. No. 104,446 8Claims. (Cl. 254134.3)

This invention relates to stringing block apparatus for use in stringingcables and more particularly to multiplepulley stringing block apparatusfor use in simultaneously stringing a plurality of cables inside-by-side relation.

It has become a common practice in the stringing operation to pull orstring a plurality of conductor cables simultaneously in side-by-siderelation. It is, of course, desirable to string or pull a plurality ofcables simultaneously in side-by-side relation and certain stringingblock devices have been developed to permit this type or" Stringingoperation. Most of the prior art devices currently now being used topermit simultaneous stringing of a plurality of cables in side-by-siderelation have been found unsatisfactory in several respects.

During the stringing operation wherein a plurality of cables aresimultaneously pulled or strung for subsequent connection to aninsulator support, a stringing block is usually suspended from aninsulator and the cables are thereafter threaded through the block bythe lead line. In the multiple stringing operation, the lead line isconnected to a running board, the latter having the conductor cablessecured thereto so that when the running board is pulled through thestringing block, the cables presumably will be seated on theirrespective sheaves or pulleys. Most of the prior art devices currentlybeing used for this type of work are exceedingly large and heavy and arecomprised of a pair of pulleys or sheaves mounted in spaced apartrelation with a central roller-like construction interposed betweenthese pulleys. The central sheave or roller is intended to accommodatethe pulling line and when the running board is pulled through the blockthe conductor cables are intended to be seated upon the outboard pulleysor sheaves. However, in the prior art devices, the central pulley has nogroove, as such, but is of hourglass configuration thus permitting agreat deal of lateral play thereupon by the pulling line. With thisarrangement, the running board will not be properly aligned with thestringing block apparatus so that the passing of the latter through thestringing block is impaired.

Another disadvantage experienced through use of the prior art devices isthat these devices will become angularly displaced with respect to thevertical prior to the passing of the running board through the stringingblock. This angular displacement of the prior art stringing block iscaused by the weight differential in the conductors being pulled and thepulling line and it has been found that the pulling line will sometimesbe outweighed as \much as six to one with respect to the conductors. Ithas, therefore, been necessary to stabilize these prior art devices bymeans of tag lines and the like.

It is, therefore, a general object of this invention to provide a novelmultiple, tandem-pulley, stringing block, of highly efficient andcompact construction for use in simultaneously and eilectively stringinga plurality of cables in side-by-side relation.

Another object of this invention is the provision of a novel andimproved multiple, tandem-pulley, stringing block of the class describedwhich is arranged and constructed to automatically adjust to the weightimbalance, attributable to the weight differential of the pulling lineand conductors being strung so that there is no noticeable increase inthe pulling tension when the running board passes over the pulleys.

Another object of this invention is the provision of a novel andimproved multiple, tandem-pulley stringing block apparatus for use insimultaneously stringing a plurality of cables in side-by-side relationand which includes a plurality of pulleys arranged in tandem pairs, thelatter serving to maintain a pulling line, conductors and passing boardin properly aligned relation throughout the stringing operation.

A still further object of this invention is the provision of a novel:and improved multiple, tandem-pulley stringing block apparatus for usein simultaneously and effectively stringing a plurality of conductorcables in side-by-side relation which includes a plurality of pulleysarranged in tandem pairs and guide means cooperating with the pulleysfor maintaining a pulling line and conductors being pulled in seatedrelation on their associated supporting pulleys during the stringingoperation.

These and other objects and advantages of my invention will more fullyappear from the following description made in connection with theaccompanying drawing wherein like character references refer to the sameor similar parts throughout the several views and in which:

FIG. 1 is a side elevational view of my invention shown suspended from aconventional insulator string and in supporting relation with aplurality of conducting cables during a stringing operation;

FIG. 2 is a side elevational view on an enlarged scale of my inventionwith certain parts thereof indicated in adjusted position by dotted lineconfiguration;

FIG. 3 is a front elevational view of the invention; and

FIG. 4 is a vertical cross sectional View taken approximately along line44 of FIG. 3 and looking in the direction of the arrows, certain partsthereof being illustrated in an adjusted position by dotted lineconfiguration.

Referring now to the drawing, it will be seen that my novel multiple,tandem-pulley stringing block apparatus, designated in its entirety bythe reference numeral 10, includes a support structure 11 comprised of apair of upstanding frame elements 12 each being of substantiallychannel-shaped cross sectional configuration and being rigidlyinterconnected at their respective lower ends by means of a transverseframe element 13. Referring to FIGS. 3 and 4, it will be seen that thetransverse element 13 is provided with a centrally located upstandingflange 14. A pair of spaced apart upstanding post elements 15 arerigidly interconnected to the transverse frame element 13 and each hasan arcuate upper end 15a as best seen in FIG. 4. The function of theupstanding post elements 15 will be described hereinbelow.

Referring now to FIG. 2 it will be seen that the upper terminal portionsof the upstanding frame elements 12 each have a block 16 welded thereto.It will be noted that the blocks 16 have a centrally and downwardlyextending recess 17 formed therein and the upper end of each block has apair of axially spaced apart cylindrical retainer elements 18 fixedlysecured thereto. It should also be pointed out that although not shownon the drawing the web portion of each of the upstanding frame elements12 is also suitably recessed and this recess will be disposed inregistering relation with the recess 17 formed in the block 16. Atriangular shaped bracket or yoke structure 19 having its respectiveends suitably apertured is positioned so that the apertured ends,thereof, are disposed between the respective cylindrica] retainers l8and a pin 29 extends through the cylindrical retainers and mountingbracket 19 and is locked in place by a cotter pin 21. The apex of thetriangular shaped mounting bracket 19 is provided with a plurality ofapertures 22 to facilitate coupling or connections thereof toconventional insulator support S as shown in FIG. 1. It will thereforebe seen that the mounting bracket permits the block to be readilyremoved from suspended relation with an insulator string after theconductors have been pulled to the desired tension. The conductors willbe attached to the insulator string by the permanent clamps andfittings.

A mounting frame structure designated generally by the reference numeral23 is pivotally mounted on the support structure 11 and this mountingframe structure includes a plurality of spaced apart, substantiallyparallel triangular mounting plates 24. It will be noted that adjacentmounting plates 24 rotatably support a pulley structure therebetween. Inthis connection, the outermost pairs of triangular mounting plates 24rotatably support a pair of outboard pulley structures 25 therebetweenwhile the innermost pair of triangular mounting plates 24 suitably mounta central pulley structure 26 therebetween. It will also be noted thatthe innermost of the triangular mounting plates associated with therespective out-board pulley structures 25 are rigidly interconnectedwith the triangular mounting plates 24 associated with the centralpulley structure 26 by means of U-shaped channel members 2'7. Each ofthese U- shaped channel members 27 includes a Web 28 and dependingflanges 29 as best seen in FIG. 4. The apex of the respective mountingplates are all suitably apertured for the reception of a pivot axle orpin 39 which passes therethrough. The pivot axle or pin 30 is of tubularconstruction and has its opposite end rigidly secured to the upstandingframe elements 12 by means of lock screws 31. It will also be noted thatspacer elements 32 are interposed between the outermost of thetriangular mounting plates 24 and their associated upstanding frameelements 12 as best seen in FIG. 3.

Referring again to FIG. 3 it will be seen that the triangular mountingplates associated with each of the pulley structures are rigidlyinterconnected by means of a bolt 33 and nut 34, the former having asuitable cylindrical spacer positioned there around for spacing theseplates in proper arrangement. Referring again to H6. 3 and FIG. 4 itwill be seen that the outboard pulley structures 25 are each comprisedof a pair of similar pulleys 25a, the pulleys of each pair beingdisposed in tandem relation while the central pulley structure 26 iscomprised of a pair of pulleys 26a also arranged in tandem relation. Itwill be seen that the pulleys 25a of the outboard pulley structures areeach provided with the conventional pulley grooves 25b while the pulleys261: comprising the central pulley unit are also provided with theconventional pulley grooves 26b and the pulleys of all of the pulleystructures are of similar construction. Referring to FIGS. 2 and 4 itwill be seen that the pulleys of each pulley structure are rotatablymounted adjacent the forward and rearward terminal portions of theirrespective associated pair of triangular mounting plates 24, the pulleyscomprising the outboard pulley structures being mounted for rotationabout axle structures 35 while the pulleys comprising the central pulleyunit are mounted for rotation about axle structures 36. It will be seenthat the axes of rotation of the pulleys comprising each of the pulleystructures is disposed on opposite sides of and slightly below the pivotpin 30. Actually, the rotational axes of the pulleys of each pulleystructure are disposed equidistant from the pin 30 and are also disposedin parallel relation with respect to the pivot pin 30.

Referring again to FIG. 3, it will be seen that the post elements 15each have a pair of hooks 37 afiixed to opposite surfaces thereof. Itwill also be noted that the triangular mounting plates 24 disposed onopposite sides of and adjacent each post 15 are also provided with hooks38 and coil springs 3? interconnect the side plates with theirassociated posts. The coil springs 39 are tension springs and serve tobias the mounting frame structure 23 towards its centrally locatedposition about its pivot pin when the mounting frame has been pivotedabout its axis of pivot. It will, therefore, be seen that the tension 4springs 39 actually constitute centering springs for centering themounting frame on the support structure during the stringing operation.

in most of the prior art devices currently being used for the multiplecable stringing operation, there is no provision for preventing thecables seated upon the respective pulleys from being laterallydisplaced. To this end, however, I have provided means for preventinglateral displacement of the respective cables and pulling lines frombeing laterally displaced from their seated relation upon the associatedpulleys.

Referring now to FIG. 3, it will be seen that a pair of guide members orgates 40 are pivotally secured to the bracket 19 and depend therefrom.These guide members 40 are of substantially channel shaped configurationand each has a pair of out-turned flanges 41. The uppermost portion ofthe gate 40 is recessed as at 42 to thereby define a pair of cars 46a.The bracket 19 is provided with a pair of depending bearings or bosses43 each supporting a pivot pin 44, the latter being secured in itsassociated bearing by means of a set screw 45. The pin 44 extendsthrough apertures formed in the flanges 41 of its associated guidemember to thereby permit pivoting movement of the guide member as bestseen in FIG. 4. Each of the guide members 40 is urged to a centraldepending position with respect to the pulley structures by means of apair of torsion springs 46, the latter being positioned around the pivotpin 44 of each guide member and on opposite sides of the latter. Thus,it will be seen that the guide members are each secured to a bracket 19for swinging movement about a substantially horizontal transverse axis.Referring again to FIG. 3 it will be seen that the guide members 40 arepositioned on opposite sides of the central pulley structure 26 and alsosubstantially traverse the space between the outboard pulleys and thecentral pulley structures. It will further be noted that the guidemembers 40 also have their lower terminal edges positioned below theupper circumferential edges of each of the pulleys so that there is nodanger of the pulling rope or conductor cables being displaced laterallyfrom their associated pulley structures.

During the stringing operation involving the stringing of a plurality ofcables simultaneously in side-by-side relation, my novel multiple,tandem-pulley stringing block apparatus 10 will be suspended from aconventional insulator string S as shown in FIG. 1. The bracket 19provides means for ready connection of the stringing block 10 to theinsulator. The particular embodiment of my novel stringing blockillustrated in the drawings will accommodate either two or threeconductors simultaneously although it will be seen that any desirednumber of conductors may be accommodated by increasing the size andnumber of pulley structures of the particular stringing block. A pullingrope P will be secured to a triangular shaped running board R in theconventional manner and the latter will have the conductor cablessecured thereto. Again, referring to FIG. 1 it will be seen that therunning board R has a pair of conductor cables C secured thereto forsimultaneous stringing. The pulling rope P will be threaded through thestringing block and will be seated upon the pulleys 26a of the centralpulley structure 26 and the pulling rope will thereafter be pulledthrough the stringing block. The pulling rope will be pulled until therunning board R has passed through the support structure 11 and theconductor cables are seated upon their respective outboard pulleystructure 25.

It has been found that when several conductors are simultaneously pulledthrough a stringing block, the conductors will greatly outweigh thepulling rope so that there is a great weight differential on oppositesides of the pulley. This type of an operation causes conventionalstringing block devices to be moved from the vertical at a highdisplacement angle before the running board passes over the stringingblock and it has been found necessary in most cases to put a rope tagline on the 4441-. ..I ll

bottom of the stringing block so that this tendency towards this highdisplacement angle will be resisted. It has been found, however, aspointed out above that through the use of my device there is still aslight angular displacement but there is no increase in the pullingtension because of the tandem arrangement of the pulleys of each pulleystructure. There is also a tendency of the insulator string to becomeslightly displaced from the vertical but the weight of the block itselftends to overcome this tendency and the pivotal action between thesupport structure and the mounting support frame allow the pulleystructures themselves to oscillate in a direction to offset the angulardisplacement. It will, therefore, be seen that the disadvantage of thenecessity of tag lines associated with the prior art devices plus theincrease in pulling tension are completely obviated by my novelstringing block apparatus.

It will also be seen that the tandem arrangement of the pulleys of thecentral pulley structure cooperates with the pulling cable to hold theentire stringing block apparatus square or in alignment with respect tothe running board and therefore prevents hang-up of the board againstthe support structure 11. The tandem arrangement of the cables of theoutboard pulley structures, of course, substantially reduce the bendingmoment of the cables as the conductor cables pass over these pulleystructures and also facilitates even support and passage of the runningboard over the stringing block apparatus.

The guide members 40 cooperate with the support structure 11 and therespective pulleys of each of the pulley structures to preventaccidental lateral displacement of the cables from one pulley structureto another. Since these gates or guide members 40 are readily pivotal attheir respective axis of pivot, the gates will readily pivot whenencountered by the running board when the latter is pulled over thestringing block apparatus and will thereafter be urged to theirdepending centered relation. When the mounting frame structure 23 pivotsrelative to the support structure 11, this pivoting action takes placeagainst the bias of the tension springs 39 which tend to center themounting frame structure on the support structure. The depending flanges29 of the U-shaped channel member 27 engage the edges of the upstandingposts 15 to limit pivoting movement of the mounting frame structure 23so that movement of the pulley structure beyond a predetermined point isprevented.

It will, therefore, be seen from the foregoing description that I haveprovided a novel multiple tandem-pulley stringing apparatus which isreadily adaptable for use in efiiciently stringing a plurality ofconductor cables simultaneously in side-by-side relation. It will alsobe noted from the foregoing description that my novel multiple,tandem-pulley stringing apparatus obviates the necessity of the use oftag lines thus rendering the stringing operation through the use of mydevice more economical than was heretofore possible with conventionalstringing devices.

It will also be noted that my novel stringing block apparatus isarranged and constructed to assure positive alignment of the runningboard when the latter passes over the stringing block thus preventingany tendency of the latter to bind with regard to the stringing blockapparatus and also prevents any tendency of the cables from becominglaterally displaced from their seated relation upon their associatedpulleys.

Thus, it will be seen that I have provided a novel and improvedmultiple, tandem-pulley stringing apparatus which is not only of highlyefficient and inexpensive construction but functions in a more efiicientmanner than any heretofore known comparable devices.

It will, of course, be understood that various changes may be made inthe form, details, arrangement and proportions of the various partswithout departing from the general scope of my invention.

What is claimed is:

1. Multiple-pulley stringing block apparatus for use in simultaneouslystringing a plurality of cables in side-byside relation, said apparatuscomprising a support structure including a pair of upstanding,spaced-apart frame elements, a bracket member having "opposite sidesthereof connected to said frame elements and being readily connectibleto a support such as an insulator, a mounting frame structure pivotallymounted on said support structure for pivotal movement relative thereto,a central pulley structure rotatably mounted on said mounting framestructure centrally thereof, a pair of outboard pulley structuresrotatably mounted on said mounting frame structure on opposite sides ofand in substantially parallel relation and with said central pulleystructure, each of said pulley structures being comprised of a pair ofsimilar pulleys disposed in tandem relation, and the rotational axis ofthe respective pulleys comprising each pulley struc ture each beingdisposed on opposite sides of and substantially equidistant from theaxis of pivot of said mounting frame structure.

2. The multiple-pulley, stringing block apparatus as defined in claim 1and cooperating stop means on said support structure and mounting framestructure respectively for limiting pivotal movement of the latter aboutits axis of pivot.

3. The multiple-pulley, stringing block apparatus as defined in claim 1wherein the pulleys of said pulley structures which are disposed on thesame side of the axis of pivot of said mounting frame structure havetheir rotational axes disposed in substantial coaxial relation.

4. The multiple-pulley, stringing block apparatus as defined in claim 1and a pair of spaced apart-guide members pivotally connected with saidbracket member and depending therefrom and being disposed insubstantially upstanding relation on opposite sides of said centralpulley structure and serving to prevent accidental displacement ofcables from one pulley structure to another.

5. The multiple-pulley, stringing block apparatus as defined in claim 1and resilient means interposed between said mounting frame structure andsaid support structure and yieldably resisting relative pivotal movementtherebetween.

6. Multiple-pulley, stringing block apparatus for use in simultaneouslystringing a plurality of cables in sideby-side relation, said apparatuscomprising a support structure having coupling means for readyconnection thereof to a support such as an insulator, a mounting framestructure pivotally mounted on said support structure for pivotalmovement relative thereto, a central pulley structure mounted on saidmounting frame structure centrally thereof, a pair of outboard pulleystructures rotatably mounted on said mounting frame structure onopposite sides of and in substantial parallel relation with said centralpulley structure, each of said pulley structures being comprised of apair of similar pulleys disposed in tandem relation and being mountedfor rotation about axis disposed substantially parallel to the axis ofpivot of said mounting frame structure, and a pair of spaced-apart guidemembers pivotally connected with said support structure for pivotalmovement relative thereto and being disposed in upstanding relation onopposite sides of said central pulley structure and serving to preventaccidental lateral displacement of a cable from one pulley structure toanother.

7. Multiple-pulley, stringing block apparatus for use in simultaneouslystringing a plurality of cables in sideby-side relation, said apparatuscomprising a support structure having coupling means for readyconnection thereof to a support such as an insulator, a mounting framestructure pivotally mounted on said support structure for pivotalmovement relative thereto, a central pulley structure mounted on saidmounting frame structure centrally thereof, a pair of outboard pulleystructures rotatably mounted on said mounting frame structure onopposite sides of and in substantially parallel relation with saidcentral pulley structure, each of said pulley posed in tandem relationand being mounted for rotation I about an axis disposed substantiallyparallel to the axis of pivot of said mounting frame structure, andcooperating stop mean on said support structure and mounting framestructure respectively for limiting pivoting movement of the latterabout its axis of pivot.

8. Multiple-pulley, stringing block apparatus for use in simultaneouslystringing a plurality of cables in sideby-side relation, said apparatuscomprising, a support structure having coupling means for readyconnection thereof to a support such as an insulator, a mounting framestructure pivotally mounted on said support structure for pivotalmovement relative thereto, a central pulley structure mounted on saidmounting frame structure centrally thereof, a pair of outboard pulleystructures rotatably mounted on said mounting frame structure onopposite sides of and in substantially parallel relation With saidcentral pulley structure, each of said pulley structures being comprisedof a pair of similar pulleys disposed in tandem relation, and therotational axes of the respective pulleys comprising each pulleystructure being disposed on opposite sides of and substantiallyequidistant from the axis of the pivot of said mounting frame.

References Cited in the file of this patent UNITED STATES PATENTS584,566 Sullivan June 15, 1897 961,510 Mack June 14, 1910 1,796,251Greve Mar. 10, 1931 1,841,292 Lark Jan. 12, 1932 2,294,850 OstranderSept. 1, 1942 2,770,430 Albright Nov. 13, 1956 3,012,756 Cronkright Dec.12, 1961 FOREIGN PATENTS 940,034 France May 10, 1948 1,080,382 FranceMay 26, 1954 1,059,523 Germany June 18, 1959 1,069,728 Germany Nov. 26,1959

1. MULTIPLE-PULLEY STRINGING BLOCK APPARATUS FOR USE IN SIMULTANEOUSLYSTRINGING A PLURALITY OF CABLES IN SIDE-BYSIDE RELATION, SAID APPARATUSCOMPRISING A SUPPORT STRUCTURE INCLUDING A PAIR OF UPSTANDING,SPACED-APART FRAME ELEMENTS, A BRACKET MEMBER HAVING OPPOSITE SIDESTHEREOF CONNECTED TO SAID FRAME ELEMENTS AND BEING READILY CONNECTIBLETO A SUPPORT SUCH AS AN INSULATOR, A MOUNTING FRAME STRUCTURE PIVOTALLYMOUNTED ON SAID SUPPORT STRUCTURE FOR PIVOTAL MOVEMENT RELATIVE THERETO,A CENTRAL PULLEY STRUCTURE ROTATABLY MOUNTED ON SAID MOUNTING FRAMESTRUCTURE CENTRALLY THEREOF, A PAIR OF OUTBOARD PULLEY STRUCTURESROTATABLY MOUNTED ON SAID MOUNTING FRAME STRUCTURE ON OPPOSITE SIDES OFAND IN SUBSTANTIALLY PARALLEL RELATION AND WITH SAID CENTRAL PULLEYSTRUCTURE, EACH OF SAID PULLEY STRUCTURES BEING COMPRISED OF A PAIR OFSIMILAR PULLEYS DISPOSED IN TANDEM RELATION, AND THE ROTATIONAL AXIS OFTHE RESPECTIVE PULLEYS COMPRISING EACH PULLEY STRUCTURE EACH BEINGDISPOSED ON OPPOSITE SIDES OF AND SUBSTANTIALLY EQUIDISTANT FROM THEAXIS OF PIVOT OF SAID MOUNTING FRAME STRUCTURE.